Ingot extracting device

ABSTRACT

A device for extracting ingots from molds of plasma-arc furnaces in which a dummy bar is secured on at least two rods located symmetrically relative to a center of its cross-section.

Unite States Patent [191 Nautny et a1.

[54] INGOT EXTRACTING DEVICE [22] Filed: Dec. 15, 1971 [21] Appl. No.: 208,085

[52] 11.8. CI. ..164/274, 164/252, 164/282 [51] Int. Cl. ..B22d 111/08 [58] Field of Search ..164/52, 64, 82, 252,

[111 3,734,165 1 May 22, 1973 [56] References Cited UNlTED STATES PATENTS 1,961,399 6/1934 Snook 164/82 3,388,736 6/1968 Accary et ai. 3,496,280 2/1970 Dukelow et al ..l64/252 UX FOREIGN PATENTS OR APPLICATIONS 854,176 11/1960 Great Britain 164/52 Primary Examiner-R. Spencer Annear Attorney-Holman & Stern [5 7 ABSTRACT A device for extracting ingots from molds of plasmaarc furnaces in which a dummy bar is secured on at least two rods located symmetrically relative to a center of its cross-section.

2 Claims, 1 Drawing Figure L l K///////// INGOT EXTRACTING DEVICE BACKGROUND OF THE INVENTION The present invention relates to electrometallurgy and more particularly to devices for extracting ingots from molds of plasma-arc furnaces.

PRIOR ART Widely known is a device for extracting ingots from plasma-arc furnaces incorporating an ingot chamber located under the molds, in which chamber reciprocates a dummy bar fast at the end of a rod connected to a power source and kinematically associated with a drive mounted on a frame attached to the ingot chamber.

However, such devices are of the single-rod type and are suited for extracting ingots of either round or rectangular cross-section with a cross-sectional side ratio not over 3:1. The ingots produced in such furnace are not applicable to sheet rolling without being exposed to an additional hot-forming operation either on cogging mills or on powerful presses. These supplementary intermediate technological operations needed to prepare ingots of certain high-grade metals, such as titanium, for rolling lead to a considerable reduction in labor productivity, loss of time and additional expenditures. Thus, in rollinga titanium slab into sheets, an intermediate operation involving an initial breakdown to obtain the requisite reduction in cross-section results in heavy losses of expensive metal. One of the reasons lies, first of all, in the fact that heating of titanium is liable to cause intense oxidation along with the formation of a brittle layer stretching to a large depth and subject to subsequent removal.

The use of single-rod devices for extracting the ingots with a cross-sectional side ratio of 3:1 and over is impractical as friction forces arising between the mold walls and the ingot being extracted, differ in value and have large arms which may result in substantial bending moments acting on a joint between the rod and the dummy bar which, in turn, may cause emergency conditions. Besides, in melting flat ingots, there are limitations as to the diameter of the rod, and this tends to decrease its rigidity and does not permit strong currents to be passed through it to the ingot (in view of permissible current density). In the meantime in modern furnaces very strong currents ranging within l-25 thousands of amperes and more shall be supplied to the ingots.

It is an object of the present invention to provide a device for extracting ingots from a mold of a plasmaarc furnace having a design ensuring a smooth extraction of heavy ingots with a cross-sectional side ratio of at least 3:1.

SUMMARY OF THE INVENTION According to the above and other objects in a device for extracting ingots from molds of plasma-arc furnaces including an ingot chamber located under the mold and designed to accommodate a reciprocating dummy bar fast at the end of a rod connected to a power supply source and linked mechanically to a drive set up on a frame coupled with the ingot chamber, in accordance with this invention, for extracting ingots with a crosssectional side ratio of at least 1:3, the dummy bar is secured to at any rate two rods positioned symmetrically relative to a center of the dummy bar cross-section with the total cross-sectional area of the rods assuring a density of the feed current up to 1.5-2 A/mm BRIEF DESCRIPTION OF THE DRAWINGS Described below is an exemplary embodiment of the DETAILED DESCRIPTION OF THE INVENTION An ingot extracting device consists of an ingot chamber l defined by a water-cooled sleeve of rectangular cross-section and, whose upper portion is connected to a mold casing (not shown in the drawing).

The ingot chamber 1 houses a water-cooled dummy bar 2 secured rigidly on two rods 3 serving to move the dummy bar 2 and the rods pass through holes in a bottom of the chamber 1 provided with rod ways 4 fitted with vacuum seals 5 and placed under the holes.

The rods 3 are spaced apart at a distance ensuring to the best advantage a rigidity of a dummy bar-rod unit. The rods 3 are hollow and the wall thickness does not exceed 10 mm and the rods are provided with water cdoling.

The total cross-sectional area of the rods 3 shall assure a density of the feed current up to 1.5-2 A/mm.

In order to pass the requisite current to the ingot through the rods, their number can be increased with the rods disposed uniformly over the cross-section of the dummy bar 2 (ingot). The interior of the rods 3 serves for feeding and discharging cooling water to and from the dummy bar 2.

Secured to a lower part of the rods 3 are threaded bushings 6 in which feed spindles 7 are threaded. The free ends of the feed spindles 7 are attached in bearing units 8, while the tails of the feed spindles 7 have fastened rigidly thereto gear wheels 9 meshing with a drive gear 10 fitted on a tail shaft of reversing drive 11. The drive 11 is mounted on a frame 12 which also carries all of the units of the present device and an upper flange of the frame 12 is connected to the ingot chamber 1.

The device functions as follows:

Prior to the beginning of the melting process, a metal sheet of the metal, to be remelted, is secured on the dummy bar 2, whereupon the dummy bar 2 together with the sheet is fed into the mold. As ingot 13 is being melted, it is drawn out of the mold by the dummy bar 2 descending together with the rods 3.

The rods 3 with the dummy bar 2 attached to its ends are shifted by the feed spindles 7 threaded in the threaded bushings 6 set in motion by the gear wheels 9 through the drive gear 10 coupled to the drive 11.

A synchronism in motion of the rods 3 is attained because the feed spindles 7 have a similar pitch and the gear wheels 9 secured to their tails a similar number of teeth. The rate of the extraction of the ingot 13 from the mold is adjustable with a range of 1:10.

After.the ingot 13 is melted and fed for discharging, the drive 11 is reversed and the feed spindles 7 start unthreading from the bushings 6 thus pushing the rods 3 together with the dummy bar 2 attached to their ends upwardly to be discharged.

The present device provides for a reciprocating movement of the dummy bar 2 in the ingot chamber 1 both at operating and sustained speeds.

In addition the present device for extracting ingots permits a feeding of the requisite current to an ingot and accomplishes a extraction of an ingot with the cross-sectional side ratio of at least 3:1 from the mold.

The invention described and illustrated is believed to admit of numerous modifications within the ability of persons skilled in the art, and all such modifications are considered within the spirit and scope of the appended claims.

We claim:

1. A device for extracting ingots from molds of plasma-arc furnaces, comprising an ingot chamber located under the mold; a dummy bar enclosed in said ingot chamber and arranged to reciprocate therein; said ingot chamber having a lower part; a frame connected to lower part of said ingot chamber; a drive installed on said frame; at least two rods; one end of each of said rods being fast with said dummy bar symmetrically relative to the center of its cross-section; means linking the other end of each rod mechanically to the said drive and said drive being coupled to a power source; the total cross-sectional area of said rods assuring a density of the feed current up to 1.5-2 A/mm.

2. The device for extracting ingots from molds of plasma-arc furnaces as claimed in claim 1 in which each rod is hollow, with the interior of the rod serving for feeding and discharging a coolant to and from the dummy bar, said means linking the other end of each rod mechanically to the drive including a threaded bushing for each rod, a feed spindle threaded in each bushing, a gear wheel fixed to each spindle, said drive having a drive gear, and each gear wheel being in mesh with the drive gear, said drive being of reversing type. l 

1. A device for extracting ingots from molds of plasma-arc furnaces, comprising an ingot chamber located under the mold; a dummy bar enclosed in said ingot chamber and arranged to reciprocate therein; said ingot chamber having a lower part; a frame connected to lower part of said ingot chamber; a drive installed on said frame; at least two rods; one end of each of said rods being fast with said dummy bar symmetrically relative to the center of its cross-section; means linking the other end of each rod mechanically to the said drive and said drive being coupled to a power source; the total cross-sectional area of said rods assuring a density of the feed current up to 1.5-2 A/mm2.
 2. The device for extracting ingots from molds of plasma-arc furnaces as claimed in claim 1 in which each rod is hollow, with the interior of the rod serving for feeding and discharging a coolant to and from the dummy bar, said means linking the other end of each rod mechanically to the drive including a threaded bushing for each rod, a feed spindle threaded in each bushing, a gear wheel fixed to each spindle, said drive having a drive gear, and each gear wheel being in mesh with the drive gear, said drive being of reversing type. 